Question

2005 Chevy Malibu LT shifting problems. Automatic transmission.

Hello! My wife has a 2005 Chevy Malibu LT 3.5L and I had a question pertaining to shifting. It's an automatic transmission and well for starters, the electronic range control switch on the shifter is out so when you manually change between 1,2,3,4 gears it stays in L3.

The real question is, does that have anything to do with my transmission not catching gears correctly? Like for example if I am driving, ANY speed over say 15 mph (2nd gear and up) and I let off the gas for a few seconds, then apply pressure to it again my engine surges up catches the gear below the correct one jerking the car forward and then goes into the correct gear.

Example: 35 mph let off gas, surges up to 2,500 rpm no torque at all catches gear and jerks forward with the correct rpm. I know it's wrong because it used to not do this at all but no dealership or transmission shop can help.

I've run snap on tests on the transmission, all solenoids are up to par no codes except for electric range control switch and no check engine light.